Many industrial processes result in a waste stream liquor which contains some amount of a desired material. Examples of this would be corn oil in the manufacture of ethanol, tall oil in the manufacture of pulp and paper, and other industries requiring organic separation from the process, such as petroleum. Oftentimes, this chemistry involves the use of surfactants to break the emulsion and release the desired oil from the liquor.
At times, silicates such as precipitated or fumed silicon dioxide, diatomaceous earth, talc, or volcanic ash, among others, are added to the surfactant to further enhance the separation of the desired oil from the liquor. The surface of the silicate may be treated with a hydrophobic compound such as silicone, polyethylene, bee's wax, or stearic acid for example, but not limited to these examples, as there are other viable options. The treatment makes the silicate hydrophobic which can further enhance the performance of the demulsifying compound. The prior art in this field notes that either hydrophobic silicate, hydrophilic silicate, or a mixture thereof is preferable in corn oil demulsification.
The use of chemicals to separate organic components from aqueous waste streams has a long and varied history with the challenge of corn oil demulsification being the most recent to emerge. Initially, all non-aqueous liquids were reintroduced into the solid materials collected as the fat content for animal feed (dried distillers grain with solubles, or DDGS). However, it was determined that the corn oil could be successfully used as a raw material for the production of bio-diesel fuel. This renewable source of diesel fuel was a boom to the ethanol fermentation sector and ignited a determined effort to reclaim this material from the waste stream. The initial method used was in the use of centrifuges, or mechanical methods to separate the individual components in the liquor. The results, which were successful, however, were also inconsistent in the yield of this material. In the early to mid-2000's chemicals were investigated as additives to assist with the separation. Various surfactants were introduced with the most successful being the ethoxylated sorbitan esters. The use of a formulated product (multi-components) was introduced later in the development scheme. Silica and its treated counterpart, hydrophobic silica, were some of the latest components added. Other chemicals have been successfully used in this effort as well.
Initially mechanical methods for removing oil were invented, such as decanting, boiling, centrifuging, or combinations. As effective as these methods have been, oil concentrations within the water phase still remain. As noted above, chemical additives were invented as a result to supplement and enhance the mechanical methodologies, which can be seen in the prior art. Some examples of such prior art are: U.S. Pat. Nos. 4,029,596; 6,201,142; 8,192,627; 8,841,469 and 8,962,059.
Prior art in this field relies on chemically weakening the micelle strength encapsulating the oil within the water, with or without a physical rupturing of the micelle by a solid particle dispersed within. Thus, the oil is released from suspension and able to be more readily extracted by the traditional mechanical methods noted above.
Applicant's inventive silicate addresses and solves the problems in the industry related to oil separation in waste streams. Wide varieties of chemical additives for oil separation have been created and are available. However, there is a need for an improved additive for both effectiveness and efficiency, and it is to this need that this invention is directed.